'Cyrus' stars John C Reilly as John, a divorced man who meets the woman of his dreams Molly (Marisa Tomei) - only to discover that he has become entangled in a bizarre love triangle with another man, her 21-year-old son Cyrus (Jonah Hill).

What appealed to you about your character in 'Cyrus'?
John C Reilly:
I like the fact that he has gotten to a place in his life where he has nothing to lose. So he tells the truth constantly until he is put in a position with Cyrus, where he has to start lying to keep his relationship going with Molly. I love the first couple of scenes. He's been divorced for seven years, he has been in an emotional spiral and then there is a jump-start when his ex-wife tells him she is getting remarried and that shocks him into action. He puts himself out there one more time.

I like the way he is still emotionally vulnerable enough to go after love. He is beaten down at the beginning of the movie, then he takes that risk and meets this girl, Molly. Something happens, there is a spark and he cleans up his apartment and tries to make himself loveable again.

I like the hopefulness of the character in that way. He is a more mature character than I have played recently. He is slightly different from some of the more broad 'man-child' characters I have been playing. I get to play my age instead of trying to pretend I am 12-years-old. [Llaughs]

It must have been refreshing.
It was. In 'Walk Hard' I had to play 14-years-old - literally. From 14 to 60. 'Step Brothers' involved channelling my inner 12-year-old. But I also like this movie because it is truthful; it is an honest movie and has a genuine emotional core. And the way the characters talk to each other really is the way people communicate in life.

We had a script for this movie but usually everyday we chucked it and were told to put everything in our own words and be as honest as we could be. The biggest sin for the Duplass brothers [directors] is if it seems like a movie. 'No, no, no. That seems too much like a movie, like some kind of preconceived idea,' they say. 'Let's just find what is really going on in this room today between these three people'.

John is very brave. In the movie he gets the dance party going at the party even though he is quite shy. Are you the life and soul of the party?
I am not the cool movie star guy at parties despite what other people might think. I've gotten better at social situations from having to do interviews like this actually. I grew up acting, doing plays and musicals and I think one of the reasons I got into acting in the first place was because I was always more comfortable inhabiting a character than having to be myself in some situations. I've lost track of who that really is [laughs], but I am most comfortable at parties when I know everyone there.

How did you get started in acting? You weren't an extrovert?
I was not an extrovert, I was someone who enjoyed goofing around with my friends, but I don't think you have to be an extrovert to be an actor. I've gotten used to having to speak publicly as myself just because I have been forced to do that. After a while you start to relax a little bit and embrace people who want you to speak and be yourself. But when I am acting I don't think of it as me. I think what allowed me from an early age to be an actor was that it was like wearing a mask and I could hide behind the mask.

What does that party scene in 'Cyrus' with Marisa Tomei say about relationships do you think?
What it says about our characters is that we are both people who are tired of the artifice of dating and preconceived rules people have. There are rules like 'Don't call back right away', 'Don't get your heart broken', 'Play it safe'. We are both at the point in our lives where we are thinking we want something real and different.

Molly hasn't had a long term guy in her life for a long time and I've been divorced for seven years. I am in a broken emotional state and we both arrive at this party looking for someone who is willing to accept us as who we are. We are both looking for someone who is willing to hear the truth.

I think that's more common than movies lead you to believe. Often people are attracted to each other not so much for how they look or how much money they have, or for status or whatever. They are looking at people's emotional status, where they are in their lives and what they are looking for in a partner.

How interesting is it for you playing the romantic lead?
It is fun to be the guy who gets the girl every once in a while. I've played a lot of different parts and I've played romantic parts in the past but I personally get a little uncomfortable having to do smoochy stuff because it's a little more intimate than I am used to. But it is a lot of fun too because I think of myself as a romantic person. Not to be corny, but it is all about the power of love and I'm generally a positive, optimistic person, so I like playing characters like John.

How much of you is in this character?
I have been happily married for a long time so I am not in the emotional place that John is in, but I can relate to the more emotionally vulnerable moments he has. I guess I have a lot in common with his instincts because his instincts were mine. For example they [the directors] would say: 'If you came out of the room to check on your girlfriend and her grown son was standing there in his underwear with a knife, how would you react? Go. Action'. So a lot of the reactions and my facial expressions are real. I was really going by the seat of my pants. Circumstantially, I don't have that much in common with the character but emotionally and instinctively I do quite a bit.

What are your criteria for taking a role?
I used to base it totally on the character: 'Is this a character I want to play?' 'Is this something I have done before? If not it might be interesting'. I still think about character a lot, because the truth is there is so little you can control as an actor and because film is a director's medium.

So I ask: 'Is this a character I can believe in?' 'Is this something I can feel connected to?' Beyond that I look for people who are inspired and have a vision for what they are doing. A good sign is something that happened on this movie, someone offers me a part and says: 'You are the only person I can see playing this part'. Now that means they thought about it, they have a vision for what the story should be and I fit into that vision.

When there is a job that comes along and I hear: 'Oh you know what, I am offering you this part and if you don't give us an answer by Monday morning I am giving it to so and so'. I say: 'Well go to so and so, then'.

And that really happens?
Yes that happens. They might say: 'A movie is happening on this date no matter who is in it. We've got the money, we've got the date and we need an actor'. I am less interested in things that I would come 'jobbing' into and I am more interested in films that are going to utilise my unique gifts. You've also got to find those 'dignified pay outs', those 'dignified sell outs', so money matters. A 'dignified pay out' is where there is something for me to do and they happen to have some money to pay me. Those are few and far between.

How refreshing is it to make a unique film like 'Cyrus'?
It is very refreshing. I have done a lot of different kinds of movies: I have done big action movies and big comedies. I have also done kids' movies. I enjoy having variety in my work. But it is getting hard to find a place for someone like me who really likes to be a storyteller and become immersed in a character.

Often in this age of 'American Idol' I wonder where someone like me fits in. I'm an actor and not really a celebrity. Every time someone says to me: 'Oh you are a celebrity' I honestly don't think of myself in that way. I didn't become an actor to become famous or wealthy: I did it because this is what I love to do. I think that there is a lot of money to be made on sequels and movies based on toys, but there are also people carrying the torch for great stories.

'Cyrus' is in cinemas now.